In general, such containers are formed from an elongated tubular body portion, such as a cylinder, which is closed by end caps. Usually, the end caps are dished, and convex outwardly. Two support frames are provided at each end of the cylindrical container for lifting, stacking and the like. Alternatively, the container may be mounted in a framework. In other cases, the container may be fixedly mounted to a truck body, chassis or framework. In general, such containers are made to International Standard Organisation (ISO) specifications. Although, they may be of any other shape, size or construction, and may be made to other standards and specifications.
Where it is necessary to provide an opening such as, for example, a hand opening or a man opening into the container, in general, such openings are provided on the cylindrical surface. An opening of the desired size, usually circular, is cut in the cylindrical surface. A tubular member formed by a substantially circular side wall which is longitudinally seam-welded, and which forms portion of a neck frame is set into the opening and welded to and around the periphery of the opening. A compensating flange, which also forms part of the neck frame to compensate for the loss of inherent strength in the container as a result of forming the opening, is then welded around the side wall and also to the container. Brackets to pivotally support eye bolts for securing a closure member, namely a lid, to the neck frame are usually welded in pairs around the outer surface of the side wall.
This construction of neck frame has many disadvantages. Firstly, the construction of the neck and welding it to the container is a slow, tedious and time consuming task. Secondly, and more importantly, it has been found that welding the side walls of the neck frame to the container opening and the flange causes considerable distortion of both the container and the tubular neck. Thirdly, the actual welding of the tubular neck and compensating flange to the container causes further loss of inherent strength of the container. Fourthly, the welding of the eye brackets to the tubular neck further leads to distortion of the neck. Distortion of the tubular neck, it will be appreciated, is a particular serious matter. Since in most cases it is essential that the lid must sealably engage the tubular neck, any distortion in the neck will prevent the formation of an adequate seal between the lid and the tubular neck. To overcome this problem, and to achieve some form of reasonable seal between the lid and the tubular neck, it has in the past been necessary to carry out further machining to either the tubular neck after it and the compensating flange have been welded to the container, and/or alternatively, to carry out further machining to the lid to compensate for the distortion. This is particularly unsatisfactory, in that in most cases it is particularly difficult to machine the neck after it has been welded into position, and machining of the lid is also only a partly satisfactory solution.
There is therefore a need for a neck frame which overcomes the problems of neck frames known heretofore.